TSUMUGU · B1 (est.) · 字
咕
ㄍㄨ · gū
verb/onom — to coo, rumble, mutter (a low sound)
字源 FORM — what the parts do
Tgǔ → gū — the tone flattens to first for the sound-word
A mouth (口) making a low, rolling sound — coo, rumble, mutter. 古 gǔ carries the sound, flattened to gū to name the noise itself. Doubled and paired it copies the sound: 咕咕 (a dove), 咕嚕 (a rumble), 嘀咕 (to mutter under the breath).
故事 STORY — a scene to remember it by
嘴巴（口）半閉著，喉嚨裡低低一滾——咕、咕。
The mouth (口) half-closed, a low roll down in the throat — coo, coo.
字源記憶法
意 · Meanings
(本義)咕咕、咕嚕— to coo, rumble (low sound)常用
→嘀咕— to mutter under the breath常用
(本義) original meaning · → ⇒ each arrow = one more step of extension
關 · Related
呱guāsame plus a phonetic, but 呱 takes 瓜 (melon) for a louder cry; 咕 takes for the low coo